﻿/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Net.Sockets;
#if !PLATFORM_COMPACTFRAMEWORK  
using System.Net.Security;
#endif
using System.Net;
using System.Globalization;
using System.Security.Cryptography.X509Certificates;
#if !PLATFORM_COMPACTFRAMEWORK  
using System.Security.Authentication;
#endif
using EffiProz.Core;
using EffiProz.Core.RowIO;
using EffiProz.Core.Lib;
using EffiProz.Core.Lib.IO;
using EffiProz.Core.Results;
using EffiProz.Core.Errors;
using EffiProz.Core.DataTypes;
using EffiProz.Core.Navigators;

/**
 * Base remote session proxy implementation. Uses instances of Result to
 * transmit and recieve data. This implementation utilises the updated HSQL
 * protocol.
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.7.2
 */
namespace EffiProz.Core.Server
{
    public class ClientConnection : SessionInterface
    {

        public const String NETWORK_COMPATIBILITY_VERSION = "0.1.0.1";
        public const int NETWORK_COMPATIBILITY_VERSION_INT = -0010000;

        const string _certificateName = "Certificate";

        const int BUFFER_SIZE = 0x1000;
        byte[] mainBuffer = new byte[BUFFER_SIZE];
        private bool _isClosed;
        private TcpClient socket;
        protected DataOutputStream dataOutput;
        protected DataInputStream dataInput;
        protected RowOutputInterface rowOut;
        protected RowInputBinary rowIn;
        private Result resultOut;
        private long sessionID;
        private long lobIDSequence;

        //
        private bool _isReadOnly = false;
        private bool _isAutoCommit = true;
        private int zoneSeconds;
        private Scanner scanner;
        private String zoneString;
        private Calendar calendar;

        //
        protected String host;
        protected int port;
        protected String path;
        protected String database;
        protected bool isTLS;
        protected int databaseID;

        public ClientConnection(String host, int port, String path,
                                    String database, bool isTLS, String user,
                                    String password, int timeZoneSeconds)
        {

            this.host = host;
            this.port = port;
            this.path = path;
            this.database = database;
            this.isTLS = isTLS;
            this.zoneSeconds = timeZoneSeconds;
#if !PLATFORM_COMPACTFRAMEWORK  
            this.zoneString = TimeZoneInfo.Local.StandardName;
#endif

            initStructures();

            Result login = Result.newConnectionAttemptRequest(user, password,
                database, zoneString, timeZoneSeconds);

            initConnection(host, port, isTLS);

            Result resultIn = execute(login);

            if (resultIn.isError())
            {

                /** @todo fredt - review error message */
                throw Error.error(resultIn);
            }

            sessionID = resultIn.getSessionId();
            databaseID = resultIn.getDatabaseId();
        }

        /**
         * resultOut is reused to trasmit all remote calls for session management.
         * Here the structure is preset for sending attributes.
         */
        private void initStructures()
        {
            RowOutputBinary rowOutTemp = new RowOutputBinary(mainBuffer);

            rowOut = rowOutTemp;
            rowIn = new RowInputBinary(rowOutTemp);
            resultOut = Result.newSessionAttributesResult();

        }

        protected virtual void initConnection(String host, int port,
                                      bool isTLS)
        {
            openConnection(host, port, isTLS);
        }

#if !PLATFORM_COMPACTFRAMEWORK   
        private bool ValidateServerCertificate(
              object sender,
              X509Certificate certificate,
              X509Chain chain,
              SslPolicyErrors sslPolicyErrors)
        {
            if (sslPolicyErrors == SslPolicyErrors.None)
                return true;
            else if (sslPolicyErrors == SslPolicyErrors.RemoteCertificateChainErrors
                && certificate.Subject == certificate.Issuer &&
                chain.ChainElements.Count == 1)
                return true;
          
            // Do not allow this client to communicate with unauthenticated servers.
            return false; 
        }
#endif
        private Stream GetClientStream(TcpClient client, bool isTLS)
        {
#if !PLATFORM_COMPACTFRAMEWORK  
            if (isTLS)
            {
                // Create an SSL stream that will close the client's stream.
                SslStream sslStream = new SslStream(
                    client.GetStream(),
                    false,
                    new RemoteCertificateValidationCallback(ValidateServerCertificate),
                    null
                    );

                sslStream.AuthenticateAsClient("EffiProz");

                return sslStream;
            }
            else
#endif
            {
                return client.GetStream();
            }
        }


        protected void openConnection(String host, int port,
                                      bool isTLS)
        {

            try
            {

                socket = new TcpClient(host, port);
                socket.NoDelay = true;
                socket.ReceiveTimeout = 1000;
                socket.SendTimeout = 1000;

                Stream clientStream = GetClientStream(socket, isTLS);
              
                dataInput = new DataInputStream(clientStream);
                dataOutput = new DataOutputStream(clientStream);  
            
            }
            catch (Exception e)
            {

                throw new CoreException(e, Error.getStateString(ErrorCode.X_08001),
                                     -ErrorCode.X_08001);
            }
        }

        protected void closeConnection()
        {

            try
            {
                if (socket != null)
                {
                    socket.Close();
                }
            }
            catch (Exception) { }

            socket = null;
        }

        public virtual Result execute(Result r)
        {
            lock (this)
            {
                try
                {
                    r.sessionID = sessionID;
                    r.databaseID = databaseID;

                    write(r);

                    return read();
                }
                catch (Exception e)
                {
                    throw Error.error(ErrorCode.X_08006, e.ToString());
                }
            }
        }

        public RowSetNavigatorClient getRows(long navigatorId,
           int offset, int size)
        {
            lock (this)
            {
                try
                {
                    resultOut.setResultType(ResultConstants.REQUESTDATA);
                    resultOut.setResultId(navigatorId);
                    resultOut.setUpdateCount(offset);
                    resultOut.setFetchSize(size);

                    Result result = execute(resultOut);

                    return (RowSetNavigatorClient)result.getNavigator();
                }
                catch (Exception e)
                {
                    throw Error.error(ErrorCode.X_08006, e.ToString());
                }
            }
        }

        public void closeNavigator(long navigatorId)
        {
            lock (this)
            {
                try
                {
                    resultOut.setResultType(ResultConstants.CLOSE_RESULT);
                    resultOut.setResultId(navigatorId);
                    execute(resultOut);
                }
                catch (Exception ) { }
            }
        }

        public void close()
        {
            lock (this)
            {
                if (_isClosed)
                {
                    return;
                }

                _isClosed = true;

                try
                {
                    resultOut.setResultType(ResultConstants.DISCONNECT);
                    execute(resultOut);
                }
                catch (Exception) { }

                try
                {
                    closeConnection();
                }
                catch (Exception) { }
            }
        }

        public Object getAttribute(int id)
        {
            lock (this)
            {

                resultOut.setResultType(ResultConstants.GETSESSIONATTR);
                resultOut.setStatementType(id);

                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }

                Object[] data = rin.getSingleRowData();

                switch (id)
                {

                    case SessionInfoConsts.INFO_AUTOCOMMIT:
                        return data[SessionInfoTypeConsts.INFO_BOOLEAN];

                    case SessionInfoConsts.INFO_CONNECTION_READONLY:
                        return data[SessionInfoTypeConsts.INFO_BOOLEAN];

                    case SessionInfoConsts.INFO_ISOLATION:
                        return data[SessionInfoTypeConsts.INFO_INTEGER];

                    case SessionInfoConsts.INFO_CATALOG:
                        return data[SessionInfoTypeConsts.INFO_VARCHAR];
                }

                return null;
            }
        }

        public void setAttribute(int id, Object property)
        {
            lock (this)
            {
                resultOut.setResultType(ResultConstants.SETSESSIONATTR);

                Object[] data = resultOut.getSingleRowData();

                data[SessionInfoTypeConsts.INFO_ID] = (id);

                switch (id)
                {

                    case SessionInfoConsts.INFO_AUTOCOMMIT:
                    case SessionInfoConsts.INFO_CONNECTION_READONLY:
                        data[SessionInfoTypeConsts.INFO_BOOLEAN] = property;
                        break;

                    case SessionInfoConsts.INFO_ISOLATION:
                        data[SessionInfoTypeConsts.INFO_INTEGER] = property;
                        break;

                    case SessionInfoConsts.INFO_CATALOG:
                        data[SessionInfoTypeConsts.INFO_VARCHAR] = property;
                        break;
                }

                Result resultIn = execute(resultOut);

                if (resultIn.isError())
                {
                    throw Error.error(resultIn);
                }
            }
        }

        public bool isReadOnlyDefault()
        {
            lock (this)
            {
                Object info = getAttribute((int)SessionInfoConsts.INFO_CONNECTION_READONLY);

                _isReadOnly = ((bool)info);

                return _isReadOnly;
            }
        }

        public void setReadOnlyDefault(bool mode)
        {
            lock (this)
            {
                if (mode != _isReadOnly)
                {
                    setAttribute( (int)SessionInfoConsts.INFO_CONNECTION_READONLY, mode ? true
                                      : false);

                    _isReadOnly = mode;
                }
            }
        }

        public bool isAutoCommit()
        {
            lock (this)
            {
                Object info = getAttribute((int)SessionInfoConsts.INFO_AUTOCOMMIT);

                _isAutoCommit = Convert.ToBoolean(info);

                return _isAutoCommit;
            }
        }

        public void setAutoCommit(bool mode)
        {
            lock (this)
            {
                if (mode != _isAutoCommit)
                {
                    setAttribute((int)SessionInfoConsts
                                          .INFO_AUTOCOMMIT,mode ? true
                                      : false);

                    _isAutoCommit = mode;
                }
            }
        }

        public void setIsolationDefault(int level)
        {
            lock (this)
            {
                setAttribute(level,
                             (int)SessionInfoConsts.INFO_ISOLATION);
            }
        }

        public int getIsolation()
        {
            lock (this)
            {
                Object info = getAttribute((int)SessionInfoConsts.INFO_ISOLATION);

                return Convert.ToInt32(info);
            }
        }

        public bool isClosed()
        {
            return _isClosed;
        }

        public Session getSession()
        {
            return null;
        }

        public void startPhasedTransaction() { }

        public void prepareCommit()
        {
            lock (this)
            {
                resultOut.setAsTransactionEndRequest(ResultConstants.PREPARECOMMIT,
                                            null);
                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public void commit(bool chain)
        {
            lock (this)
            {
                resultOut.setAsTransactionEndRequest(ResultConstants.TX_COMMIT,
                                            null);
                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public void rollback(bool chain)
        {
            lock (this)
            {
                resultOut.setAsTransactionEndRequest(ResultConstants.TX_ROLLBACK,
                                            null);
                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public void rollbackToSavepoint(String name)
        {
            lock (this)
            {
                resultOut.setAsTransactionEndRequest(ResultConstants.TX_SAVEPOINT_NAME_ROLLBACK,
                                            name);
                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public void savepoint(String name)
        {
            lock (this)
            {
                Result result = Result.newSetSavepointRequest(name);
                Result rin = execute(result);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public void releaseSavepoint(String name)
        {
            lock (this)
            {
                resultOut.setAsTransactionEndRequest(ResultConstants.TX_SAVEPOINT_NAME_RELEASE,
                                            name);
                Result rin = execute(resultOut);

                if (rin.isError())
                {
                    throw Error.error(rin);
                }
            }
        }

        public long getId()
        {
            lock (this)
            {
                return sessionID;
            }
        }

        public void addWarning(CoreException warning) { }

        /**
         * Used by pooled connections to reset the server-side session to a new
         * one. In case of failure, the connection is closed.
         *
         * When the Connection.close() method is called, a pooled connection calls
         * this method instead of HSQLClientConnection.close(). It can then
         * reuse the HSQLClientConnection object with no further initialisation.
         *
         */
        public void resetSession()
        {
            lock (this)
            {
                Result login = Result.newResetSessionRequest();
                Result resultIn = execute(login);

                if (resultIn.isError())
                {
                    _isClosed = true;

                    closeConnection();

                    throw Error.error(resultIn);
                }

                sessionID = resultIn.getSessionId();
                databaseID = resultIn.getDatabaseId();
            }
        }

        protected virtual void write(Result r)
        {
            r.write(dataOutput, rowOut);
        }

        protected virtual Result read()
        {

            Result result = Result.newResult(dataInput, rowIn);

            result.readAdditionalResults(this, dataInput, rowIn);
            rowOut.setBuffer(mainBuffer);
            rowIn.resetRow(mainBuffer.Length);

            return result;
        }

        /**
     * Never called on this class
     */
        public String getInternalConnectionURL()
        {
            lock (this)
            {
                return null;
            }
        }

        public long getLobId()
        {
            lock (this)
            {
                return lobIDSequence++;
            }
        }

        public BlobDataID createBlob(long length)
        {

            BlobDataID blob = new BlobDataID(getLobId());

            return blob;
        }

        public ClobDataID createClob(long length)
        {

            ClobDataID clob = new ClobDataID(getLobId());

            return clob;
        }


        public void allocateResultLob(ResultLob resultLob,
                                    Stream dataInput) { }

        public Scanner getScanner()
        {

            if (scanner == null)
            {
                scanner = new Scanner();
            }

            return scanner;
        }

        public Calendar getCalendar()
        {

            if (calendar == null)
            {
                //TimeZone zone = TimeZone.getTimeZone(zoneString);

                //calendar = new GregorianCalendar(zone);
                calendar = new GregorianCalendar();
            }

            return calendar;
        }

        public TimestampData getCurrentDate()
        {

            long currentMillis = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;
            long seconds = EfzDateTime.getCurrentDateMillis(currentMillis) / 1000;

            return new TimestampData(seconds);
        }

        public int getZoneSeconds()
        {
            return zoneSeconds;
        }

        public int getStreamBlockSize()
        {
            return 512 * 1024;
        }

        /**
         * Converts specified encoded integer to a Network Compatibility Version
         * String. The tranmitted integer is negative to distinguish it from
         * 7 bit ASCII characters.
         */
        static public String toNetCompVersionString(int i)
        {

            StringBuilder sb = new StringBuilder();

            i *= -1;

            sb.Append(i / 1000000);

            i %= 1000000;

            sb.Append('.');
            sb.Append(i / 10000);

            i %= 10000;

            sb.Append('.');
            sb.Append(i / 100);

            i %= 100;

            sb.Append('.');
            sb.Append(i);

            return sb.ToString();
        }

        
    }
}
